Dr C Mary Schooling and colleagues publish an explanation for the higher rates of cardiovascular disease among men than women.

Dr C Mary Schooling and colleagues publish in BMC Medicine: Testosterone therapy and cardiovascular events among men: a systematic review and meta-analysis of placebo-controlled randomized trials. At any given age men have higher rates of cardiovascular disease than women, which was previously attributed to lower levels of estrogens among men than women. However, large trials many years ago showed that estrogen therapy does not protect men or women against cardiovascular disease. The alternative hypothesis that men have higher rates of cardiovascular disease than women because men have higher levels of testosterone or other androgens than women has rarely been considered, although very high levels of androgens are thought to damage the cardiovascular system. This publication shows, based on “gold-standard evidence” that testosterone therapy does indeed increase the risk of a cardiovascular-related event among men, equating to a number needed to harm of about 90 per year of testosterone therapy for older men. Given cardiovascular disease is the leading cause of death, the role of androgens in cardiovascular disease needs to be investigated urgently from the perspective of prevention and treatment. Notably, evidence is accumulating that some of the most effective treatments for cardiovascular disease, such as statins, lower testosterone.